eq1:=x^2-x*cos(y)-x1:x1 may be considered as a parameter. On the first run of the analyzer the intermediary files described in the previous section will be generated and at run time the value of x1 will be substituted by the value indicated in the parameter file. After this first run and if you want to analyze the system with another value for x1 you may use the pre-processing mechanism described in the previous section and just change the value of x1 in the parameter file. See section 12.4.6.1 for an example of the analysis of parametric system.
Each line of the parameter file indicates a name of a parameter and its value. Thus
x1 1is a valid parameter file. To indicate a parameter file to the analyzer use the -P argument followed by the name of the parameter file.
A special case of parameter may be used to speed up the
computation. Assume that you have a system with large numerical
constants (by "large" we mean that the string representing the
numerical values has a large number of characters). Each evaluation of
your system will require first to read the strings representing the
numerical constants and then to convert it in a float number. It may
therefore be interesting to store once the constants values and to
substitute them in the analytical form of the equations by symbols
which may be attached to these values. This may be done by
substituting the numerical constants by symbols of the form _IA where
is an integer starting from 0. These parameters have
then to be stored in a parameter file. Thus, for example, consider the
equations:
eq1:=1.12345678901*x1+4.563213456789222:Using MAPLE you may easily change this equation to:
eq1:=_IA0*x1+_IA1:and store the values in a parameter file:
_IA0 1.12345678901 _IA1 4.563213456789222When reading the parameter file the program will store in a special array the value of the parameters whose name start by the symbol _IA. Then, when the parser find a symbol starting with this symbol it will determine the number following this keyword (which is the value of the index in the parameter table) and will just substitute the corresponding value found in the parameter table. Hence when evaluating an expression the parser will have to read less character and avoid unnecessary conversion from a string to a double. Note that these parameters must be numbered in sequence, starting from 0.