Compose versus Composition

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Compose versus Composition*From*: bss at physics.att.com*Date*: Sun, 24 Jan 93 15:19:47 EST

Dear Mathgroup, Version 1 of MMA had a "Compose" function which is very convenient for a particular kind of operation. I need to apply a set of "Heads" to a set of "variables" in order to form a matrix of functions (these are natural in quantum calculations of "Slater determinants"), and under MMA version 1, a simple command produces this matrix. A simple example is with two functions f and g : ---------------------------------------------------------------- In[35]:= Outer[Compose,{f,g},{x,y}] Compose::obsfn: Compose is an obsolete function, superseded by Composition. Out[35]= {{f[x], f[y]}, {g[x], g[y]}} ------------------------------------------------------------ Under MMA version 2 and later I have been unable to figure out any way of doing this with Composition, Map,... For the moment I am carrying on, ignoring the ugly error messages, but would like to know how it is done in version 2. Any suggestions? Sriram Shastry bss at physics.att.com Jan 24 , 93 Murray Hill