subst SciMax Toolbox substpart

SciMax Toolbox >> substinpart

substinpart

Maxima Function

Calling Sequence

substinpart (x, expr, n_1, ..., n_k)

Description

Similar to substpart, but substinpart works on the internal representation of expr.

Examples:

(%i1) x . 'diff (f(x), x, 2);
                              2
                             d
(%o1)                   x . (--- (f(x)))
                               2
                             dx
(%i2) substinpart (d^2, %, 2);
                                  2
(%o2)                        x . d
(%i3) substinpart (f1, f[1](x + 1), 0);
(%o3)                       f1(x + 1)

If the last argument to a part function is a list of indices then several subexpressions are picked out, each one corresponding to an index of the list. Thus

(%i1) part (x + y + z, [1, 3]);
(%o1)                         z + x

piece holds the value of the last expression selected when using the part functions. It is set during the execution of the function and thus may be referred to in the function itself as shown below. If partswitch is set to true then end is returned when a selected part of an expression doesn't exist, otherwise an error message is given.

(%i1) expr: 27*y^3 + 54*x*y^2 + 36*x^2*y + y + 8*x^3 + x + 1;
              3         2       2            3
(%o1)     27 y  + 54 x y  + 36 x  y + y + 8 x  + x + 1
(%i2) part (expr, 2, [1, 3]);
                                  2
(%o2)                         54 y
(%i3) sqrt (piece/54);
(%o3)                        abs(y)
(%i4) substpart (factor (piece), expr, [1, 2, 3, 5]);
                               3
(%o4)               (3 y + 2 x)  + y + x + 1
(%i5) expr: 1/x + y/x - 1/z;
                             1   y   1
(%o5)                      - - + - + -
                             z   x   x
(%i6) substpart (xthru (piece), expr, [2, 3]);
                            y + 1   1
(%o6)                       ----- - -
                              x     z

Also, setting the option inflag to true and calling part or substpart is the same as calling inpart or substinpart.

subst SciMax Toolbox substpart