mf_assert.hlp

是一个经济学管理应用软件 很难找的 但是经济学学生又必须用到

{smcl}
{* 15mar2005}{...}
{cmd:help mata assert()}
{hline}
{* index assert()}{...}
{* index asserteq()}{...}

{title:Title}

{p 4 4 2}
{bf:[M-5] assert() -- Abort execution if false}


{title:Syntax}

{p 8 8 2}
{it:void} 
{cmd:assert(}{it:real scalar r}{cmd:)}

{p 8 8 2}
{it:void} 
{cmd:asserteq(}{it:transmorphic matrix A}{cmd:,}
{it:transmorphic matrix B}{cmd:)}


{title:Description}

{p 4 4 2}
{cmd:assert(}{it:r}{cmd:)} produces the error message 
"{err:assertion is false}" and aborts with error if {it:r}==0.

{p 4 4 2}
{cmd:asserteq(}{it:A}{cmd:,} {it:B}{cmd:)} is logically equivalent to 
{cmd:assert(}{it:A}{cmd:==}{it:B}{cmd:)}.  If the assertion is false,
however, information is presented on the number of mismatches.


{title:Remarks}

{p 4 4 2}
In the midst of complicated code, you know that a certain calculation 
must produce a result greater than 0, but you worry that perhaps you 
have an error in your code:

	...
	{cmd:assert(n>0)}
	...

{p 4 4 2}
In another spot, you have produced matrix {cmd:A} and know every element 
of {cmd:A} should be positive or zero:

	...
	{cmd:assert(A:>=0)}
	...

{p 4 4 2}
Once you are convinced that your function works, these verifications should be
removed.  In a third part of your code, however, the problem is different 
if the number of rows {it:r} exceed the number of columns {it:c}.  In all the
cases you need to use it, however, {it:r} will be less than {it:c}, so you 
are not much interested in programming the alternative solution:

	...
	{cmd:assert(rows(PROBLEM) < cols(PROBLEM))}
	...

{p 4 4 2}
Leave that one in.


{title:Conformability}

    {cmd:assert(}{it:r}{cmd:)}:
		{it:r}:  1 {it:x} 1
	   {it:result}:  {it:void}

    {cmd:asserteq(}{it:A}{cmd:,} {it:B}{cmd:)}:
		{it:A}:  {it:r1 x c1}
		{it:B}:  {it:r2 x c2}
	   {it:result}:  {it:void}

	
{title:Diagnostics}

{p 4 4 2}
{cmd:assert(}{it:r}{cmd:)} aborts with error if {it:r}==0.

{p 4 4 2}
{cmd:asserteq(}{it:A}{cmd:,} {it:B}{cmd:)} aborts with error if 
{it:A}!={it:B}.


{title:Source code}

{p 4 4 2}
{view assert.mata, adopath asis:assert.mata},
{view asserteq.mata, adopath asis:asserteq.mata}


{title:Also see}

{p 4 13 2}
Manual:  {hi:[M-5] assert()}

{p 4 13 2}
Online:  help for 
{bf:{help m4_programming:[M-4] programming}}
{p_end}