Release 0.9.0 "Wilson's Dream" - Full equation library

This version integrates an extended version of the HP50G equation library that Jean Wilson has been working on for many weeks. Equations are also fully documented, with examples illustrating how to use them, and a full documentation of the variables they contain.

It also fully enables the algebraic-assisted solver, i.e. a version of the solver that attempts to isolate variables to evaluate expressions directly, which is both faster and more accurate when possible.

WARNING Equations in the current state of the library are not fully validated yet. DB48x users are invited to test them and report issues they find.

WARNING Constants used in the library are relatively accurate and have been modernized compared to the HP50G version. However, an effort is underway to compute the physical constants that are not fundamental but derived from other constants. It is expected that the numerical values returned from the equations will changeslightly as constants are udpated.

Features

• Improved equation library and documentation The equation library now features more than 650 equations, more than 700 variables, 18 sections and 158 subsections. This is roughtly twice as big as the HP50G equation library, and covers more modern aspects of science such as nuclear physics.

Bug fixes

• solver: Do not propagate errors during isolate When using the algebraic-assisted solver, errors raised by the internal calls to isolate no longer manifest as solver errors.
• units: Do not leave error behind in unit::convert_to_real This could cause spurious Inconsistent units errors while solving.
• logical: Make logical operations behave symmetrically, i.e. ensure that #100+1 and 1+#100 both return #101.
• nfunctions: Evaluate symbolic arguments symbolically and fix bugs converting arguments to decimal. The evaluation of '∫(0;1;x+1;x)' after x=3 would result in a nonsensical expression '∫(0;1;4;3)'.
• integrate: Report errors in bound evaluation. An error in the evaluation of the first bound could be "erased" if the evaluation of the second bound was successful. For example, in '∫(0;1;sin(x)/x;x)', the Divide by zero error evaluating 'sin(x)/x' at x=0 is erased by the successful evaluation at x=1 that follows.

Improvements

• equations: Accept units in isolate This allows many equations in the equation library to successfully use the symbolic approach, improving accuracy significantly.
• add/sub: Accept zero as an operand around units. An operation like 1_km+0 is now accepted, and evaluates as 1_km.

Signed-off-by: Christophe de Dinechin [email protected]