Difference in reflectivity spectra

[Titian2]

Hi,

I am just doing a comparison between the standard tmm and your tmm-fast package. The simulations im running are just on a standard quarter wave, HR reflector. I'm also comparing the values of reflectivity computed by GWINC to compare everything against .

there seems to be a subtle, but not negligable difference between the methods here. Where

Transmission_1064:                      5.36849 ppm
Transmission_1064_FAST:         5.33146 ppm .

I was wondering if maybe ive got something set up wrong ? i would love to chat about it more - stait@caltech.edu

ive also attached the wrapper for the tmm-fast function i wrote below:
tmm-fast_wrapper.txt

lambda_0 = 1064 ##nm 
materialParams = {
    1: {
        'name' : 'SiO2',
        'desc' : 'Silica - Thin film  Room Temperature',
        'n'    : 1.45,
        'k'    : 3E-8,      
        
    },
    2: {
        'name' : 'Ti:Ta2O5',
        'n'    : 2.09,       # 2020 LMA
        'k'    : 5E-8,       # Grand Coater 
        
    },

## set up aLIGO Coating Stack to benchmark functions 
num21 = 19  # number of 1-2 doublets 

# Using list comprehension to replicate the behavior of MATLAB's repmat
#  values here correspond to the keys in  the materialParams dict 

materialLayer = [1, 2] * num21 + [1, 2] * num34
materialLayer = np.array(materialLayer)

# Optical Thickness of each layer  - currently assuming all layers are 1/4 wave at lambda_
dOpt =np.ones(len(materialLayer))*0.25 
dOpt =np.array(dOpt)

___ 
Coating Properties:

Laser Wavelength:               1064.00 nm
Number of Materials:            2
Total Physical Thickness:       5.90e-06 m
Reflectivity_1064:              0.99999
Reflectivity_1064_FAST:         0.99999
Transmission_1064:              5.36849 ppm
Transmission_1064_FAST:         5.33146 ppm
stack_name:                    QW Reflector

--------- Material 1 -------------

No. Layers:			19
Total Physical Thickness:	3.49e-06 m
Refractive Index:		1.45

--------- Material 2 -------------

No. Layers:			19
Total Physical Thickness:	2.42e-06 m
Refractive Index:		2.09