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<div><a href="index.html" title="">Macaulay2Doc</a> > <a href="_getting_spstarted.html" title="">getting started</a> > <a href="_reading_spthe_spdocumentation.html" title="">reading the documentation</a></div>
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<div><h1>reading the documentation</h1>
<div><p>The documentation for Macaulay2 is available in several formats: text format while in Macaulay2, in info format, and the most important, html format. </p>
The following functions for available for accessing the documentation.<ul><li><span><a href="_apropos_lp__String_rp.html" title="symbols matching a pattern">apropos</a> -- symbols matching a pattern</span></li>
<li><span><a href="_examples.html" title="list the examples in documentation">examples</a> -- list the examples in documentation</span></li>
<li><span><a href="_help.html" title="help command">help</a> -- help command</span></li>
<li><span><a href="_view__Help.html" title="view online doc with a web browser">viewHelp</a> -- view online doc with a web browser</span></li>
<li><span><a href="_info__Help.html" title="view online doc with info">infoHelp</a> -- view online doc with info</span></li>
</ul>
<p>While in Macaulay2, type <tt>help</tt> to get a summary of the most useful ways of obtaining help on a topic or function. Type<tt>viewHelp</tt> to start the web browser (if necessary) and to point it at the page index.html in your .Macaulay2 directory. For help on a specific topic, e.g., the jacobian function, use <tt>viewHelp jacobian</tt> or <tt>viewHelp "jacobian"</tt> or if you want the documentation for jacobian of an Ideal, use <tt>viewHelp (jacobian,Ideal)</tt></p>
<p>Using 'help' instead of 'viewHelp' results in the help text appearing in your Macaulay2 session. </p>
<table class="examples"><tr><td><pre>i1 : help "jacobian"
--loading the Macaulay2 documentation from /builddir/build/BUILD/Macaulay2-1.3.1-r10737/Macaulay2/packages/Macaulay2Doc/
o1 = jacobian -- the Jacobian matrix of partial derivatives
******************************************************
See also
========
* "diff" -- differentiate or take difference
* "contract" -- contract one matrix by another
Ways to use jacobian :
======================
* "jacobian(Ideal)" -- the Jacobian matrix of the generators of an
ideal
* jacobian(MonomialIdeal), see "jacobian(Ideal)" -- the Jacobian
matrix of the generators of an ideal
* "jacobian(Matrix)" -- the matrix of partial derivatives of
polynomials in a matrix
* "jacobian(Ring)" -- the Jacobian matrix of the polynomials defining
a quotient ring
o1 : DIV</pre>
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<p>A useful tip: in emacs, if you place your cursor on one of the lines that starts with a '*', and press return, then you will get help on that topic.</p>
<table class="examples"><tr><td><pre>i2 : * "jacobian(Ideal)"
o2 = jacobian(Ideal) -- the Jacobian matrix of the generators of an ideal
********************************************************************
Synopsis
========
* Usage: jacobian I
* Function: "jacobian"
* Inputs:
* I, an ideal, in a polynomial ring
* Outputs:
* a matrix, the Jacobian matrix of partial derivatives of the
generators of I
Description
===========
This is identical to jacobian generators I. See "jacobian(Matrix)" for
more information.
+-----------------------------+
|R = QQ[x,y,z]; |
+-----------------------------+
|I = ideal(y^2-x*(x-1)*(x-13))|
+-----------------------------+
|jacobian I |
+-----------------------------+
If the ring of I is a polynomial ring over a polynomial ring, then
indeterminates in the coefficient ring are treated as constants.
+---------------------------------+
|R = ZZ[a,b,c][x,y,z] |
+---------------------------------+
|jacobian ideal(a*y*z+b*x*z+c*x*y)|
+---------------------------------+
o2 : DIV</pre>
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<p>Reading the info form of the documentation in emacs is perhaps better than using <a href="_info__Help.html" title="view online doc with info">infoHelp</a>, because the preferred way of running Macaulay2 is also in emacs. If you do so, we recommend configuring the emacs variable <tt>Info-hide-note-references</tt> so its value is <tt>hide</tt>. The reason is that the Macaulay2 documentation sets up hyperlinks with all the required text already in them, but if <tt>Info-hide-note-references</tt> is set to <tt>t</tt>, then it will insert <tt>See</tt> or <tt>see</tt> in front of the hyperlink unless it sees that word (or <tt>in</tt>) already present in the text.</p>
<p>The function <a href="_apropos_lp__String_rp.html" title="symbols matching a pattern">apropos</a> is useful to find functions and other defined symbols which match a search string. For example, to find all symbols in Macaulay2 which contain the string 'deal', use</p>
<table class="examples"><tr><td><pre>i3 : apropos "deal"
o3 = {fittingIdeal, graphIdeal, icPIdeal, Ideal, ideal, idealizer, isIdeal,
------------------------------------------------------------------------
isMonomialIdeal, monomialCurveIdeal, MonomialIdeal, monomialIdeal,
------------------------------------------------------------------------
monomialSubideal, reesIdeal, specialFiberIdeal}
o3 : List</pre>
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<p>The documentation for most functions comes with example code. You can obtain the text of this example code using <a href="_examples.html" title="list the examples in documentation">examples</a>.</p>
<table class="examples"><tr><td><pre>i4 : examples "jacobian(Ideal)"
o4 =
R = QQ[x,y,z];
I = ideal(y^2-x*(x-1)*(x-13))
jacobian I
R = ZZ[a,b,c][x,y,z]
jacobian ideal(a*y*z+b*x*z+c*x*y)</pre>
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<p>which returns it as a string. To place these on their own lines, print the string.</p>
<table class="examples"><tr><td><pre>i5 : print examples "jacobian(Ideal)"
R = QQ[x,y,z];
I = ideal(y^2-x*(x-1)*(x-13))
jacobian I
R = ZZ[a,b,c][x,y,z]
jacobian ideal(a*y*z+b*x*z+c*x*y)</pre>
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