Direct vs. Diffuse Light Input Parameters (difcol.inp)

This document describes the format for the difcol.inp file. This file provides wavelength-dependent data on the fraction of collimated (direct) light and the relative intensity of photons for each waveband.

Important: This file is only read by the model if parameter 2) Light source from model(0) or file(1) in amc.inp is set to 0.

File Format

The structure of the difcol.inp file is as follows:

  1. Number of Wavebands: The very first value in the file must be an integer representing the total number of wavebands. This number must match the value specified for parameter 18) Number of wavebands in the amc.inp file.

  2. Light Fraction and Intensity: Following the number of wavebands, the file must contain one line of data for each waveband. Each line consists of two floating-point values:

    • Direct Fraction: The first value on the line is the fraction of light that is collimated (direct) for that specific waveband. This should be a value between 0.0 and 1.0.
    • Relative Intensity: The second value is a weighting factor for the number of photons to be simulated at that waveband. This factor is multiplied by the total number of iterations (parameter 1) Iterations in amc.inp) to determine the actual number of photons simulated for the waveband.

    Data Format: The numerical values are read in free-format (list-directed). This means the numbers should be separated by spaces or commas and do not need to be aligned in fixed columns.

Example

Here is a sample difcol.inp file configured for 12 wavebands.

12
0.8 1.0
0.8 1.0
0.7 1.0
0.7 0.9
0.6 0.9
0.6 0.8
0.5 0.8
0.5 0.7
0.4 0.7
0.4 0.6
0.3 0.5
0.3 0.4

--- NOTES ---
This section is not read by the AOMC model.
Each line of data represents a waveband.
For each waveband, the values are:
[Direct Fraction] [Relative Intensity]