[PD] new expr/expr~/fexpr~ version 0.4test3
Shahrokh Yadegari
syadegar at man104-1.ucsd.edu
Thu Jul 11 10:16:02 CEST 2002
Hi,
I have been away from this list for a while. Looking at the archives,
I noticed there has been some questions about expr.
I have a new version of expr/expr~/fexpr~ (0.4test3) with many changes. I
would appreciate hearing from anybody trying it before passing it to
Miller to be integrated in the full release. I hope this release would
address some of the raised concerns. I have not compiled this version for
NT yet, and I suspect that it will not compile, specially due to the
introduction of many new math functions. If you try it, let me know how
it goes.
You can see the documentation and download the new version at:
http:/www.crca.ucsd.edu/~yadegari/expr.html
There are major changes to this version:
- values defined by the "value" object can now be accessed like C
variables.
e.g. "expr 5 + xval", will look up the value of variable 'xval' (defined
by "value" object) and add 5 to it
- multiple expressions, separated by semicolon, resulting in multiple
outlets, can be defined in a single expr/expr~/fexpr~ object
- the if() function taking 3 arguments implemented:
if (condition, IfTrue-expr, IfFalse-expr)
for expr~ if the condition is a vector the condition is tested sample
by sample
- the previous values of the multiple outputs can be accessed by $y#[idx]
where <#> is the number of the expression and <idx> is the index.
New shorthand notations have been added for fexpr~ to make writing
filter expressions easier:
$x -> $x1[0]
$x# -> $x#[0] e.g., $x2 -> $x2[0]
$y -> $y1[-1]
$y# -> $y#[-1] e.g., $y2 -> $y2[-1]
- new math functions:
cbrt - cube root
erf - error function
erfc - complementary error function
expm1 - exponential minus 1,
log1p - logarithm of 1 plus
isinf - is the value infinite,
finite - is the value finite
isnan -- is the result a nan (Not a number)
copysign - copy sign of a number
ldexp - multiply floating-point number by integral power of 2
imodf - get signed integral value from floating-point number
modf - get signed fractional value from floating-point number
drem - floating-point remainder function
Thanks to Orm Finnendahl for sending in the following functions:
fmod - floating-point remainder function
ceil - ceiling function: smallest integral value not less than
argument
floor - largest integral value not greater than argument
Many of these changes were made so that one could use fexpr~ for solving
non-linear differential equations. The help file (help-expr.pd) includes
an example of generating chaotic signals using fexpr~ and Lorenz
equations.
Enjoy,
Shahrokh.
sdy at ucsd.edu
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