fnder是个什么函数？
fnder是matlab中的函数吗？是什么函数？在哪个工具箱里？ 用help 查一下就查出来了 splines工具箱里的 FNDER Differentiate a function.FNDER(F) returns the (representation of the) first derivative of the
univariate function contained in F (and in the same form).
FNDER(F,DORDER) returns the DORDER-th derivative, with DORDER expected
to be of the form in case the function in F is m-variate,
and, for each i=1,..,m,dian integer to indicate that the function
in F is to be differentiated di-fold with respect to its i-th argument.
Here, di may be negative, resulting in di-fold integration with respect
to the i-th argument.
FNDER(...) does not work for rational splines; for them, use FNTLR instead.
FNDER(...) works for functions in stform only in a very limited way, namely
only for type tp00, and, for that, DORDER can only be or .
Examples:
fnval( fnder( sp, 2), 3.14 );
gives the value at 3.14 of the function in sp, while
sp0 = fnint( fnder( sp ) );
gives a function that differs from sp by some constant only (namely, by
its value at 0).
页:
[1]