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# Inspiration Pad Pro 3.0 Logarithm

edited April 2016
Hello to you all

While creating a generator for jewelry finds we run in the problem that the natural logarithm still available in Inspiration Pad Pro 2.0 isn't any longer supported in version 3.0.

Has anyone an idea why the function natural logarithm (ln) got kicked out?
Does anyone have an idea how to replace this ln?

Thank you for your ideas and help.

Sincerely
Tacitus

• Dang it, until you mentioned natural logs, I didn't even know I wanted them!

The following code isn't pretty, but it's correct within several decimal places:
```table: test
ln(1) = &#91;@NaturalLog with 1&#93;\n&
ln(2) = &#91;@NaturalLog with 2&#93;\n&
ln(3) = &#91;@NaturalLog with 3&#93;\n&
ln(4) = &#91;@NaturalLog with 4&#93;\n&
ln(5) = &#91;@NaturalLog with 5&#93;\n&
ln(6) = &#91;@NaturalLog with 6&#93;\n&
ln(7) = &#91;@NaturalLog with 7&#93;\n&
ln(8) = &#91;@NaturalLog with 8&#93;\n&
ln(9) = &#91;@NaturalLog with 9&#93;\n&
ln(10) = &#91;@NaturalLog with 10&#93;\n&
ln(20) = &#91;@NaturalLog with 20&#93;\n&
ln(30) = &#91;@NaturalLog with 30&#93;\n&
ln(40) = &#91;@NaturalLog with 40&#93;\n&
ln(50) = &#91;@NaturalLog with 50&#93;\n&
ln(60) = &#91;@NaturalLog with 60&#93;\n&
ln(70) = &#91;@NaturalLog with 70&#93;\n&
ln(80) = &#91;@NaturalLog with 80&#93;\n&
ln(90) = &#91;@NaturalLog with 90&#93;\n&
ln(100) = &#91;@NaturalLog with 100&#93;\n&
ln(200) = &#91;@NaturalLog with 200&#93;\n&
ln(300) = &#91;@NaturalLog with 300&#93;\n&
ln(400) = &#91;@NaturalLog with 400&#93;\n&
ln(500) = &#91;@NaturalLog with 500&#93;\n&
ln(600) = &#91;@NaturalLog with 600&#93;\n&
ln(700) = &#91;@NaturalLog with 700&#93;\n&
ln(800) = &#91;@NaturalLog with 800&#93;\n&
ln(900) = &#91;@NaturalLog with 900&#93;\n&
ln(1000) = &#91;@NaturalLog with 1000&#93;

table: NaturalLog
{e==2.718281828459}&
{tgt=={\$1}}&
{prevLow==0}&
{prevHigh==-1}&
{exp==10}&
{newTry==e^exp}&
&#91;@40 subNaturalLog&#93;&
{round(exp*1000000)/1000000}

table: subNaturalLog
{diff=={(newTry-tgt)*1000000000}}&
&#91;when not&#93;{abs(diff)}&lt;0.001&#91;do&#93;&#91;#{diff/abs(diff)+2} subNaturalLogTryAgain&#93;&#91;end&#93;&
{newTry==e^exp}

table: subNaturalLogTryAgain
1:{prevLow==exp}&#91;when&#93;{prevHigh}&lt;0&#91;do&#93;{exp==exp+1}&#91;else&#93;{exp==exp+((prevHigh-exp)/2)}&#91;end&#93;
2:{prevHigh==exp}{exp==exp+((prevLow-exp)/2)}
```
Hope it's useful!
• Thank you very much largando!

Will let you know as soon as I have tested it.