BigStack RPN Calculator
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RPN calculators don't tend to get a lot of new users. Most users of RPN calculators have been using them for a long time. If you've used an RPN calculator before, the BigStack RPN Calculator shouldn't present you with many surprises (how to adjust precision may be one). But if you're looking for the nitty-gritty details on usage of the BigStack RPN Calculator, or you are new to RPN calculators, read on!
If you are using the Lite Version of the BigStack RPN Calculator, your functionality will be limited to what's available in the "Big-Button" Mode.
Contents
- - Nomenclature
- - Operational Modes
- - Settings
- - Entering numbers
- - The Stack
- - Scientific Operations
- - Statistics Operations
- - Operating on Sample Data
- - Upper-Tail Probabilities
- - Generating Random Numbers
- - Combinations
- - Permutations
- - The "Big-Button" Mode
Nomenclature
The following screen shot indicates the various sections of the screen on the BigStack RPN Calculator which will be referred to in the usage instructions that follow.
In some of the instructions that follow, the light gray area above the stack that contains the Trig Mode / Statistics Count Indicator, Display Mode Indicator, Precision Indicator, and the Additional Stack Values Indicator, will be referred to as the Feedback Area.
As is conventional with RPN calculators, the X value on the stack refers to the lowest value on the stack – the one on which operations will be performed first (8.2 in the image above) – Y refers to the value above this on the stack (1.7391 in the image); and Z refers to the next value, the third (99 in the image). Additional values on the stack have no label attached to them.
Operational Modes
There are three operational modes available in the BigStack RPN calculator: the scientific mode, the statistics mode, and the "big-button" mode. The mode can be toggled by tapping the 
button. When the operational mode is toggled, the buttons on the screen will change. In the scientific and statistics modes, the only changes occur to the buttons in the Mode Operations section. When in the "big-button" mode, the entire layout of the buttons will change; the buttons will increase in size and, as a result, there will be fewer commands available.
When in the scientific operational mode, the Trig Mode / Statistics Count Indicator will indicate the trig mode. When in the statistics operational mode, this indicator will display the number of entries entered on the statistics stack. While in the "big-button" mode, the Trig Mode Indicator is not shown at all.
Settings
There are two types of settings: those that can be set directly in the BigStack RPN Calculator, and those that can be set from within the iPhone's own Settings application.
Settings within the BigStack RPN Calculator
The settings that can be controlled within the BigStack RPN Calculator are the trigonometric mode, the display mode, and the precision being shown. The current value for each setting is shown in the Feedback Area at the top of the stack.
Trigonometric Mode
The trigonometric mode can be toggled between radians and degrees by tapping the 
button. When the button is tapped, the current trigonometric mode will be indicated by the Trig Mode Indicator in the Feedback Area if you are in the scientific operational mode. If you tap the button while in the statistics operational mode, the trigonometric mode will still be toggled, but the change will not be indicated in the Feedback Area.
Display Mode
The display mode can be toggled between fixed, precision, scientific, and engineering by tapping the 
button. When the button is tapped, the display mode will be toggled and the current mode will be indicated by the Display Mode Indicator in the Feedback Area.
For those not familiar with all of the available display modes, here's a quick explanation.
- - Fixed: Values will always be displayed with a fixed number of decimal places indicated by the precision. For example: 20.0000.
- - Precision: Values will always be shown using the smallest number of characters possible, up to the given precision. This will result in values sometimes being shown in a fixed mode and sometimes being shown in a scientific mode. But unlike those other modes, the precision will only be shown up to the point where it is significant. For example, if you enter a value of 20.0000, this will be shown as 20 with no decimal values ever shown since they are not significant, regardless of how the precision is set.
- - Scientific: This is sometimes referred to as exponential notation. Values will always be displayed with an exponent. For example: 2.000e+01.
- - Engineering: Values will always be shown in scientific notation, but the exponential value will always be divisible by 3. For example, if you enter a value of 20.0000, this will be shown as 20.00e+00.
Display Precision
The precision used in the display of values can be adjusted by tapping directly on the stack itself. Tapping the left side of the stack will increase the precision. Tapping the right side of the stack will decrease the precision. The precision can be adjusted from 2 to 12, though when in Engineering mode the minimum precision available is 4. The current precision is always indicated by the Precision Indicator in the Feedback Area.
This image indicates the areas of the stack to be tapped to either increase or decrease the precision (the tap targets are indicated with the pink color, but you will not actually see this color on your iPhone).
Settings in the iPhone Settings Application
The other settings can be found in the iPhone Settings application. To adjust these settings, go to the Home screen of your iPhone by tapping the Home button and locate the Settings application. Tap the icon for the Settings application to run it. Scroll down to find the settings for the BigStack RPN Calculator. It should look something like this:
Tap the BigStack row in the Settings and you'll be taken to the page that lets you adjust the settings for the BigStack RPN Calculator. It should look something like this:
Let's look at each setting individually...
General - Keyboard Clicks
Toggle this value On and Off to control if a sound is made when buttons are tapped.
General - European Formatting
By default, values in the BigStack RPN Calculator are shown using a period (.) to separate the decimal component of the number and a comma (,) to separate thousands in the non-decimal portion of the number. For example, 1,000,000.00 would represent the number one million. Some European countries swap the period and the comma so that one million would be represented as 1.000.000,00.
Turning this setting to On will result in numbers on the stack and the Stack Entry Area being shown using the European format. In addition, the 
button in the Numeric Entry section will be updated to show as 
instead.
Stack Display - Commify Numbers
Toggle this value On and Off to control if numbers shown on the stack include commas to separate thousands or not. If this value is set to off, the number one million would be displayed as 1000000.00 (assuming fixed-2 display) while if it is on, the number would be displayed as 1,000,000.00.
Stack Entry Display - Commify Numbers
This control provides a separate setting for the commification of numbers in the Stack Entry Area. Some people like displaying the commas in the stack values but find the inclusion of commas in the values as they are being entered a bit distracting.
Version Number
This isn't an actual setting. But it does allow you to see what version of the BigStack RPN Calculator you are using.
Entering Numbers
Hopefully the general concept of how to enter numbers is obvious. You tap the buttons corresponding to the numbers you want and they are placed in the Stack Entry Area. But there are some special considerations that may not be obvious to all...
Changing Sign
When entering a value in the Stack Entry Area, you can change the sign of the number by tapping the 
button. If the value you are entering is positive, it will become negative. If it is already negative, it will become positive.
Entering Exponential Values
Exponential values can be entered using the 
button. To start, enter the mantissa of the number and toggle the sign if needed (once the button is tapped, you can not change the sign of your number without deleting the exponential value first). Then tap the button and enter the exponential value. Once the button is tapped and an exponential value is entered, you can toggle the sign of the exponent using the button.
Editing Values
When entering values on the stack, there are two ways you can edit the value that has been entered. Tapping the 
button will delete the last value entered in the Stack Entry Area. Tapping the 
button will delete the entire value entered in the Stack Entry Area.
Putting Values on the Stack
When you are done entering a value in the Stack Entry Area you have two options. You can tap the 
button and the value will be moved onto the stack. Or, if you are going to be performing an operation by tapping one of the buttons in the Operations area or one of the Stack Control buttons, you can skip tapping the button; when you tap one of these buttons if there is a value in the Stack Entry Area it will be moved onto the stack before the operation is performed.
The Stack
As is conventional with RPN calculators, the X value on the stack refers to the lowest value on the stack – the one on which operations will be performed first – Y refers to the value above this on the stack (the second value); and Z refers to the next value, the third. Additional values on the stack have no label attached to them.
The BigStack RPN Calculator places no limits on the size of the stack. There are limits to how big the stack can be that are based on available memory, but that limit will vary, and it should be rather large.
The BigStack RPN Calculator displays 15 total stack values; one for the Stack Entry Area, and up to 14 values that are already on the stack. If the stack contains more values than can be displayed, the Additional Stack Values Indicator in the Feedback Area will indicate the number of additional stack values which are not currently visible.
Swap
You can swap the X and Y values on the stack by tapping the 
button. If nothing is entered in the Stack Entry Area, this will swap the existing X and Y values on the stack. If a value has been entered in the Stack Entry Area, that value will be pushed onto the stack (as X) and then the swap will occur.
Rotate
You can rotate the entire stack up by tapping the 
button. When this button is tapped, every value on the stack is moved up one position, and the value at the top of the stack is moved to the bottom, into the X location. If a value has been entered in the Stack Entry Area prior to the button tap, that value will be pushed onto the stack (as X) and then the rotation will occur which will place the just-entered value at the Y location in the stack.
You can rotate the entire stack down by tapping the 
button. When this button is tapped, every value on the stack is moved down one position, and the value at the bottom of the stack (the X value) is moved to the top of the stack. If a value has been entered in the Stack Entry Area prior to the button tap, that value will be pushed onto the stack (as X) and then the rotation will occur which will place the just-entered value at the very top of the stack.
The stack can also be rotated more quickly by swiping either up or down in the stack display area. Swipe up with a single finger to rotate the stack up, swipe down with a single finger to rotate the stack down. The longer the swipe, the greater the number of stack rotations made.
Duplicate
There is no button specifically designated for duplication. However if no value has been entered in the Stack Entry Area, tapping the button will result in duplication of the value in the X position of the stack.
Delete
When a new value is being entered in the Stack Entry Area, the stack itself can not have any values deleted as both of the delete buttons will apply to the Stack Entry Area itself. When the Stack Entry Area is empty, tapping the button will delete the stack value at the X location. Tapping the button will delete every value on the stack.
Undo
Tapping the 
button will undo the last change to the state of the stack. Up to 50 changes to the stack can be undone. Be aware that many operations result in multiple changes to the state of the stack, and each intermediate state takes up one slot in the undo history. For example, if you enter the number 3 in the Stack Entry Area and then tap the sin button, this creates two entries in the stack history; the first is the state of the stack once the value 3 has been pushed on to the stack, the second is the result of then taking the sine of this value.
The Undo button has no effect on the Stack Entry Area. Tapping Undo when you are entering a new value in the Stack Entry Area will undo the current state of the stack while leaving the value being entered untouched.
The Undo button also has no effect on the Statistics Stack, which is yet to be discussed.
Changing Sign
If the Stack Entry Area is empty, you can toggle the sign of the X value of the stack by tapping the button.
Scientific Operations
When in the scientific operational mode, the Mode Operations section of the calculator will look like this:
When in the scientific operational mode, the Trig Mode / Statistics Count Indicator in the Feedback Area will indicate the current trig mode; either deg or rad.
For anyone familiar with a scientific RPN calculator, most of the operations in the BigStack RPN Calculator should be recognizable given the text of the button. All of the trigonometric and logarithmic commands operate on the X value of the stack. For the commands that do not operate on the X value of the stack...
Delta %
The 
button computes the percentage change when comparing the X value to the Y value. Mathematically this is represented as: 100.0 * (x - y) / y.
pi
The 
button doesn't actually operate on any existing values on the stack. Rather, it places the value of pi onto the stack in the X location. If you are currently entering a value on the stack and the button is tapped, the value being entered is first put on the stack, followed by the value of pi. So the value that was being entered will be in the Y
Statistics Operations
When in the statistics operational mode, the Mode Operations section of the calculator will look like this:
When in the scientific operational mode, the Trig Mode / Statistics Count Indicator in the Feedback Area will indicate the current number entries on the Statistic Stack.
There are two main types of operations available when in the statistics operational mode: those that involve operations on sample data on the statistics stack, and those that do not. Let's look at each in turn...
Operating on Sample Data
Operations on sample data occur through the use of the statistics stack. Unlike the main stack which is always visible, the statistics stack is not visible. The count of the number of sample data points on the statistics stack is indicated in the Trig Mode / Statistics Count Indicator when you are in the statistics operational mode.
Managing the Statistics Stack
Although it is not visible, the statistics stack is easy to manage with keys that allow you to add and remove values as well as to move the statistics stack onto the display stack. One thing to keep in mind is that tapping the button has no effect on the statistics stack, this button only affects the displayed stack.
To put a single value on to the statistics stack, tap the 
button. When this button is tapped, the current X value is removed from the displayed stack and added to the statistics stack. If you were to then tap the button, the value would be placed back on the displayed stack in the X value and it would remain on the statistics stack.
To put all of the values on the displayed stack on to the statistics stack, tap the 
button – all of the values will be removed from the displayed stack and added to the statistics stack.
To remove the last value added to the statistics stack from the statistics stack, tap the 
button. This will remove the value from the statistics stack and place it in the X value of the displayed stack.
There are two ways to remove all of the values from the statistics stack. Tapping the 
button will remove all of the values from the statistics stack and place them on the displayed stack. In this way, the data from the statistics stack can be seen in its entirety, manipulated, and put back on the statistics stack as needed. Alternatively, tapping the 
button deletes every value from the statistics stack and does not place the values on the displayed stack, the statistics stack is completely cleared with no action being taken on the displayed stack.
Computing Statistics
Once the statistics stack contains values, statistics can be computed on those values. The following statistics are available:
- 
computes the mean of the values on the statistics stack.
- 
computes the median of the values on the statistics stack.
- 
computes the root-mean-square of the values on the statistics stack.
- 
computes the sum of the values on the statistics stack.
- 
computes the sample standard deviation of the values on the statistics stack.
- 
computes the population standard deviation of the values on the statistics stack.
Upper-Tail Probabilities
Normal Distributions
The upper-tail probability is computed as UTPN(m, s, x) by tapping the 
button. In this calculation, m corresponds to the mean of the distribution and this is the Z value on the stack; s corresponds to the standard deviation of the distribution (not the variance) and this is the Y value on the stack; and x corresponds to the value above which the probability will be computed and this is the X value on the stack.
Student's t-Distribution
The upper-tail probability is computed as UTPT(v, t) by tapping the 
button. In this calculation, v corresponds to an integer representing the number of degrees of freedom and this is the Y value on the stack; t corresponds to the t-statistic and this is the X value on the stack.
Chi-Square Distribution
The upper-tail probability is computed as UTPC(n, x) by tapping the 
button. In this calculation, n corresponds to an integer representing the number of degrees of freedom and this is the Y value on the stack; x corresponds to the chi-square value and this is the X value on the stack.
f-Distribution
The upper-tail probability is computed as UTPF(n1, n2, f) by tapping the 
button. In this calculation, n1 corresponds to an integer representing the number of degrees of freedom of the first sample and this is the Z value on the stack; n2 corresponds to an integer representing the number of degrees of freedom of the second sample and this is the Y value on the stack; f corresponds to the f value and this is the X value on the stack.
Generating Random Numbers
Two types of random number can be generated. Tapping 
button will generate a random number uniformly distributed in the range 0 to 1 inclusive and it will place this number on the X value of the stack. Tapping 
will generate a random number from a normal distribution with a mean of 0 and a standard deviation of 1 and it will place this number on the X value of the stack.
Combinations
The number of combinations C(y, x) can be computed by tapping the 
button.
Permutations
The number of permutations P(y, x) can be computed by tapping the 
button.
The "Big-Button" Mode
When in the "big-button" mode, the entire layout of the buttons changes; the buttons are much larger and there are fewer of them. It looks like this:
All of the commands available in the "big-button" have already been discussed, they are a subset of the commands available while in the scientific operational mode.