Editing param.rst manual page

doc/user-man/param.rst

@@ -6,15 +6,17 @@ Parameter File
 **************
 
 The main program reads an parameter file containing the parameters and
-instructions for a calculation. This file is divided into sections,
-each of which contains a different type of information. Each section
-is preceded by a blank line and starts with a line containing a
-section title in all capital letters (i.e., 'CHEMISTRY', 'UNIT_CELL',
-etc.) Each block may contain values of a sequence of variables. The
-name of each variable appears on a line by itself, followed by the
-value or (for arrays) values on one more subsequent lines. The
-order in which variables must appear within a section is fixed. The
-program stops when it encounters the block title 'FINISH'.
+instructions for a calculation. This file is divided into sections,
+each of which contains a different type of information. 
+
+Each section is preceded by a blank line and starts with a line containing 
+a section title in all capital letters (i.e., 'CHEMISTRY', 'UNIT_CELL',
+etc.) Each section may contain values of a sequence of variables. The
+name of each variable appears on a line by itself, followed by the value 
+or (for arrays) values on one more subsequent lines. The variables within
+each section must appear in a predetermined (i.e., hard-coded) order. 
+
+The program stops when it encounters the section title 'FINISH'.
 
 .. _example-sec:
 
@@ -28,16 +30,15 @@ the blocks.
 
 The first line of the file identifies the version of the file format
 (in this case, version 1.0). The remainder of the file is divided into
-sections, each of which begins with a line containing a capitalized label,
-such as MONOMERS, CHAINS, ec. Each section begins with a capitalized 
-section identtifier (MONOMER, CHAINS, etc.) on a line by itself. A single
-line must is left blank between sections. The sections are processed in 
-the order in which the appear in the parameter file. The first few sections 
-in this example simply provide values for physical and computational 
-parameters. An ITERATE section instructs the program to actually perform 
-a SCF calculation, by iteratively solving the SCF equations. A SWEEP 
-section performs a sequence of such calculations along a line in parameter 
-space. Execution of the program stops when a FINISH line is encountered.
+sections. Each section begins with a capitalized section identtifier 
+(MONOMER, CHAINS, etc.) on a line by itself. A single blank line appears 
+between sections. The sections are processed in the order in which they 
+appear in the parameter file. The first few sections in this example 
+simply provide values for physical and computational parameters. An 
+ITERATE section instructs the program to actually perform a single SCF 
+calculation, by iteratively solving the SCF equations. A SWEEP section 
+performs a sequence of such calculations along a line in parameter space. 
+Execution of the program stops when a FINISH line is encountered.
 
 ::
 
@@ -212,20 +213,23 @@ or more of the statistical segment lengths is set to unity.
 SCFT also leaves the user some freedom to redefine what he or she means 
 by a "monomer", which need not correspond to a chemical repeat unit. The 
 choice of values of the parameters block_length, solvent_size, kuhn, and
- chi to represent a particular experimental system all depend on the choice 
-of a value for a monomer reference volume, which in turn defines an effective 
-monomer repeat unit. A monomer of a polymeric species defined to be a length 
-or molar mass of chain that occupies one monomer reference volume in the melt. 
-Each element of the variable block_length represents the number of "monomers" 
-in a block of a block copolymer, defined to be the ratio of the block volume 
-to the monomer reference volume. Similarly, the variable solvent_size is given 
-by ratio of the solvent volume to the reference volume. The values of the chi 
-parameters are proportional to the reference volume, while kuhn lengths are 
-proportional to the square root of the reference volume. 
+chi to represent a particular experimental system all depend on an implicit
+choice of a value for a monomer reference volume, which defines the mononmer 
+repeat unit that is being used for bookkeeping purposes. One "monomer" of a 
+polymeric species is defined to correspond to length or molar mass of chain 
+that occupies a volume in the melt equal to one reference volume, which may
+or may not correspond to a chemical repeat unit. Each element of the variable 
+block_length represents the number of "monomers" in a block of a block 
+copolymer, which is given by the ratio of the block volume to the monomer 
+reference volume. Similarly, the variable solvent_size is given by ratio 
+of the solvent volume to the reference volume. 
 
 Note that PSCF does not require the user to input a value for the monomer 
-reference volume - the choice is implicit in the values given for other
-quantities.
+reference volume - the choice of reference volume is implicit in the values 
+given for other quantities. Changes in ones choice of reference volume lead 
+to corresponding changes in the values for the chi parameters, which are
+proportional to the reference volume, and in the kuhn lengths, which are 
+proportional to the square root of the reference volume. 
 
 **Character Strings**