.TH "compose" 3rheolef "Version 7.2" "rheolef" \" -*- nroff -*-
.ad l
.nh
.SH NAME
compose \- n-ary function application in expressions (rheolef-7\&.2)
.SH "SYNOPSIS"
.PP
.PP
.nf
template <class Function, class\&.\&.\&. Expressions>
Expression compose (const Function& f, const Expressions&\&.\&.\&. exprs);
.fi
.PP
 
.SH "DESCRIPTION"
.PP
Compose a n-ary function f with n fields in \fBinterpolate(3)\fP and \fBintegrate(3)\fP nonlinear expressions\&.
.SH "EXAMPLE"
.PP
The \fCcompose\fP operator is used for applying a user-provided function to a field: 
.PP
.nf
    Float f (Float u) { return 1/u + sqrt(u); }
    \&.\&.\&.
    field vh = interpolate (Xh, compose(f, uh));

.fi
.PP
 When two arguments are involved: 
.PP
.nf
    Float g (Float u, Float v) { return v/u + sqrt(u*v); }
    \&.\&.\&.
    field wh = interpolate (Xh, compose(g, uh, vh));

.fi
.PP
 The \fCcompose\fP operator supports general n-ary functions and class-functions\&.
.SH "CHARACTERISTIC"
.PP
The \fCcompose\fP function supports also the method of \fBcharacteristic(2)\fP used e\&.g\&. for convection-diffusion problems: 
.PP
.nf
    characteristic X (-delta_t*uh);
    test v (Xh);
    field lh = integrate (compose(uh,X)*v);

.fi
.PP
 
.SH "IMPLEMENTATION"
.PP
This documentation has been generated from file main/lib/compose\&.h 
.SH AUTHOR
Pierre  Saramito  <Pierre.Saramito@imag.fr>
.SH COPYRIGHT
Copyright   (C)  2000-2018  Pierre  Saramito  <Pierre.Saramito@imag.fr>
GPLv3+: GNU GPL version 3 or later  <http://gnu.org/licenses/gpl.html>.
This  is  free  software:  you  are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.