View source for CoCoA:FirstNonZeroPos

  <command>
    <title>FirstNonZeroPos</title>
    <short_description>the first non-zero entry in a vector</short_description>

    <description>
This function returns the index of the first non-zero entry of V.  If it
is handed a zero vector then an error is signalled.

<example>
  Use R ::= Q[x,y,z];
  V := Vector(0,0,x^2+yz,0,z^2);
  FirstNonZero(V);
x^2 + yz
-------------------------------
  FirstNonZeroPos(V);
3
-------------------------------
  V[FirstNonZeroPos(V)];
x^2 + yz
-------------------------------
</example>
    </description>

    <syntax>
FirstNonZero(V:VECTOR):POLY
</syntax>

    <see>NonZero</see>
    <see>FirstNonZero</see>

    <type>vector</type>

    <key>firstnonzeropos</key>
  </command>