Improved Answer Accuracy

When you try to reuse an answer from past calculations, TLCalc will first check to see if the answer was stored internally, and if not, TLCalc will reconstruct the value from the text. Restoring the value from text is less accurate as the internal values are stored with more decimal places than the text form. The text it reconstructs from is actually the text you see so the lower you set the number of decimal places to format in settings, the larger the rounding error when reusing past values (if the values aren't stored internally). Note that this does not affect variables and the insert ANS command which are always stored internally.

Storing the answers internally increases memory usage so 3 modes are offered:

• Store no answers: no answers are stored and consequently has minimal memory usage. This is the only mode available pre V1.19.0.
• Store constants only: only store answers if they evaluate to a constant like 2+3i. Values like matrices and expressions (2x) are not stored. This is the default mode. 
• Store all answers: all answers are stored.

The retain answer mode setting is found the Main Calculator Settings screen

Note that if you reduce the type of answers to retain such as from Store all answers to Store constants only, the internal answers are not cleared from memory until you exit and restart the app. Once the answers are removed though, the loss is permanent and only the values available by reconstructing from text becomes available.

Extra info: when you tap on a history item to toggle between rectangular and polar output, you can test whether the answer is stored internally or not. If the answer is stored internally, toggling the output type will retain the answer in black. If the answer is not stored internally, the text once toggled goes grey. When toggling answers without the internal value available, you may notice the value deviate from the original value significantly if you cycle many times. In the image below, the retain answer mode is store constants only and so 2x is not stored internally and greyed out after toggling.