## Monday, May 9, 2016

### CALC 1 Focused Calculator Customization Tutorial

CALC 1 Focused Calculator Customization Tutorial

Today is a tutorial on how to customize a calculator with CalcFxc’s CALC 1 iOS app.  In case you are new to the CALC 1 app, here is the product page:

For today’s tutorial, I am going to copy one of the financial calculators and modifying a few keys using fairly simple techniques.  My focus will be on focused calculators.   Formula calculators can be created and modified in a similar way, while form calculators cannot be modified.

Steps:

1.  Bring up the list of calculators.  On the iPod Touch/iPhone version, touch the Back button.

2.  Select Focused Calculators.

3.  We will create a copy of the new one.  In my example, I am going to copy the Financial:  TVM IYR calculator.   To do this, touch Edit.  This will bring a plus sign ( + ) on top left hand corner, with each focused calculator now accompanied with a red circle containing a minus sign ( - ).  Press the Plus sign.  This creates a copy of the top most listed focused calculator.

4.  On the copy, select the blue circle with the i (i).

5.  To edit the calculator, touch Edit on the top right hand corner of the screen.

In this tutorial, I am going to change the percentage total (%T) key, and insert the exponential (e^x) function instead.   To see the contents of any key, just touch it.  The Key Editor appears.

The Key Editor is divided into two sections:   Labels and Hints, and Formulas.  The example above is the square root (√) key in Key Editor mode.

Labels and Hints:

Label:  What is displayed on the key
Hint:  What is displayed when you press and hold on the key to bring up the help text
Insert:  What to insert when the calculator is on Algebraic mode.  It may be left blank if you want an immediate calculation.
Undo:  You can turn the ability to undo the key’s actions on or off.  The default is on.

Formulas:

Here is where you type the formulas that affect the stack.  In RPN, there are four stack levels: x, y, z, and t. On your typical calculator, the display is the x stack.  This is where you affect your output.

For instance, if your key want to calculate a function affecting the number on the x stack, you would insert the formula in the form of f(rgx()) on the x formula.

So:
x Formula:  output on the x-stack (display)
y Formula:  output on the y-stack
z Formula:  output on the z-stack
t Formula:  output on the t-stack

To access the stack elements, use the functions rgx(), rgy(), rgz(), and rgt() for the x, y, z, and t stacks, respectively.  While editing your formula, you can press the f() key to bring up the available functions for the key editor.

Also notice five other symbols on the bottom of the Key Editor screen.  They are:

Arrow pointing from paper to clipboard:  Copy the key’s contents
Arrow pointing from clipboard to paper:  Paste the key’s contents
Undo arrow:  Undo
Trash can:  Clear the key’s contents
? in a circle:  Help

6.  Going back to our example, we are going to change the percent total (%T) to the exponential key.  I only want to change the x-stack, hence I will leave the y, z, and t formulas blank.  Here is how I edited to the key.

Label:  e^x
Hint:  exponential function
Insert:  exp(
Undo:  Provide undo support.

x Formula:  exp(rgx())
y Formula:  leave blank
z Formula:  leave blank
t Formula:  leave blank

Changes are automatically saved.  You can exit editing mode and test the keys at any time.  This will take practice, testing, and maybe trial and error.

Change to percent key (%) to the natural logarithm key (ln).   Here is my set up, it is going to be the similar to the setup for the exponential key.

Label:  ln
Hint:  natural logarithm
Insert:  ln(
Undo:  Provide undo support.

x Formula:  ln(rgx())
y Formula:  leave blank
z Formula:  leave blank
t Formula:  leave blank

Change the square root key (√) to a power (exponent) key.  For this key, we are going to use two arguments (y^x).  This will require the use of both of the y-stack and x-stack.  To make the new key work in RPN mode like most RPN calculators (such as the HP-15C, HP-41, etc), I will copy the contents of the t-stack to the z-stack, while copying the z-stack to the y-stack.

Label:  power
Hint:  y^x
Insert:  ^
Undo:  Provide undo support.

x Formula:  rgy()^rgx()
y Formula:  rgz()
z Formula:  rgt()
t Formula:  rgt()

These are just some of the basics of modifying a focused calculator for the CALC 1 iOS app.

Until next time,

Eddie

This blog is property of Edward Shore, 2016.