All PartMC input files are in a text format. Each line consists of a parameter name, followed by the parameter value, and an optional comment starting with the # character. Blank lines and comment-only lines are permitted, and everything on a line after a # is completely ignored.

Parameter names are strings (normally lowercase) without spaces, such as output_prefix or del_t. The case of parameter names is significant. The order of parameters in a file is not arbitrary. Instead, they must come in the prescribed order and cannot be skipped or rearranged.

The parameter types are:

string: a single string without spaces (case is significant)
logical: a true/false value that can be the exact values "yes", "y", "true", "t", or "1" (for true values), or "no", "n", "false", "f", or "0" (for false values
integer: a positive or negative integer (depending on whether PartMC was compiled as 32bit or 64bit the maximum size will vary)
real: a floating point real number in Fortran syntax, e.g. -1.45, 5.27e10 (the available precision and range is that of whatever double precision meant during the compilation)
complex: two real numbers separated by a space, giving the real and imaginary parts of a complex number, respectively
real array: a list of real numbers separated by spaces, giving the entries of the array