Add the relative coordinates response type to the RspConverter

[GallegoSav]

This should be done for DC4 I believe.

This is related to the MEGAlib pr of Pascal where we can now ask to the response creator to use relative coordinates instead of the usual one.

It would be nice to update the RspConverter to be able to read rsp file with this new set of variables for DC4.

[jdbuhler]

I would need an example of a new rsp file to add this.

[israelmcmc]

Yes, please! :) I'd would like to see this in DC4

For context:
As a second step, after the RSP conversion, likely in a separate PR, we can implement a very simple InstrumentResponseFunction from the MEGAlib RSP matrix by:

• Projecting onto the photon axes to obtain the effective area
• Dividing the RSP matrix by both the effective area and the phase space of each bin, to get an estimate of the probability density function.
• Interpolating between bins for each event ---you can directly use histpy, the interpolation was already optimized by @jdbuhler.

This might not be as good or as fast as the NN IRF, but the simplicity is very appealing. You can directly get the results from the MEGAlib output!

The definition of the relative coordinates is here. The conversion between the CDS and the relative coordinates, as well as the calculation of the phase in relative coordinates is here. I'll merge it with the main interfaces branch soon (~next week).

There's a toy implementation of this idea here. prob_phi_arm_az_matrix is the equivalent of the response matrix that we need to compute from the MEGAlib results and the phase space. There's a comment in there "int_prob_phi_arm_az_matrix is what you would obtain from MEGAlib, and you would need to divide it by the phase space"

@GallegoSav: I'm not sure if @scipascal still plans to work on this or if he's going directly for the NN implementation --which he has working already, but outside cosipy. Let's coordinate, but yes, I think this should be done for DC4! Thanks for opening the issue.

[israelmcmc]

Oh, and I don't have an example RSP file, but I think @GallegoSav and @scipascal do, so I'll wait for their reply.

[GallegoSav]

Here an example of the header, I uploaded the file here :

``

Response Matrix 10

Version 1

Name

NM 10D imaging response

The order of the matrix

OD 10

The number of simulated events

TS 302594135032

The far-field start area (if zero a non-far-field simulation, or non-spherical start area was used)

SA 17671.5

The spectral parameters (empty if not set)

SP Linear 10 10000

The beam parameters (empty if not set)

BE FarFieldIsotropic

Are the values centered?

CE false

Is the matrix sparse?

MS true

Axis name

AN "Initial energy [keV]"

Axis type

AT 1D BinEdges

Axis data

AD 90 100 104.713 109.648 114.815 120.226 125.893 131.826 138.038 144.544 151.356 158.489 165.959 173.78 181.97 190.546 199.526 208.93 218.776 229.087 239.883 251.189 263.027 275.423 288.403 301.995 316.228 331.131 346.737 363.078 380.189 398.107 416.869 436.516 457.088 478.63 501.187 524.807 549.541 575.44 602.56 630.957 660.693 691.831 724.436 758.578 794.328 831.764 870.964 912.011 954.993 1000 1047.13 1096.48 1148.15 1202.26 1258.93 1318.26 1380.38 1445.44 1513.56 1584.89 1659.59 1737.8 1819.7 1905.46 1995.26 2089.3 2187.76 2290.87 2398.83 2511.89 2630.27 2754.23 2884.03 3019.95 3162.28 3311.31 3467.37 3630.78 3801.89 3981.07 4168.69 4365.16 4570.88 4786.3 5011.87 5248.07 5495.41 5754.4 6025.6 6309.57 6606.93 6918.31 7244.36 7585.78 7943.28 8317.64 8709.64 9120.11 9549.93 10000

Axis name

AN "#nu [deg]" "#lambda [deg]"

Axis type

AT 2D HEALPix

Axis data

AD 4 RING

Axis name

AN "Epsilon"

Axis type

AT 1D BinEdges

Axis data

AD -1 -0.99475 -0.9895 -0.98425 -0.979 -0.97375 -0.9685 -0.96325 -0.958 -0.95275 -0.9475 -0.94225 -0.937 -0.93175 -0.9265 -0.92125 -0.916 -0.91075 -0.9055 -0.90025 -0.895 -0.88975 -0.8845 -0.87925 -0.874 -0.86875 -0.8635 -0.85825 -0.853 -0.84775 -0.8425 -0.83725 -0.832 -0.82675 -0.8215 -0.81625 -0.811 -0.80575 -0.8005 -0.79525 -0.79 -0.78475 -0.7795 -0.77425 -0.769 -0.76375 -0.7585 -0.75325 -0.748 -0.74275 -0.7375 -0.73225 -0.727 -0.72175 -0.7165 -0.71125 -0.706 -0.70075 -0.6955 -0.69025 -0.685 -0.67975 -0.6745 -0.66925 -0.664 -0.65875 -0.6535 -0.64825 -0.643 -0.63775 -0.6325 -0.62725 -0.622 -0.61675 -0.6115 -0.60625 -0.601 -0.59575 -0.5905 -0.58525 -0.58 -0.57475 -0.5695 -0.56425 -0.559 -0.55375 -0.5485 -0.54325 -0.538 -0.53275 -0.5275 -0.52225 -0.517 -0.51175 -0.5065 -0.50125 -0.496 -0.49075 -0.4855 -0.48025 -0.475 -0.46975 -0.4645 -0.45925 -0.454 -0.44875 -0.4435 -0.43825 -0.433 -0.42775 -0.4225 -0.41725 -0.412 -0.40675 -0.4015 -0.39625 -0.391 -0.38575 -0.3805 -0.37525 -0.37 -0.36475 -0.3595 -0.35425 -0.349 -0.34375 -0.3385 -0.33325 -0.328 -0.32275 -0.3175 -0.31225 -0.307 -0.30175 -0.2965 -0.29125 -0.286 -0.28075 -0.2755 -0.27025 -0.265 -0.25975 -0.2545 -0.24925 -0.244 -0.23875 -0.2335 -0.22825 -0.223 -0.21775 -0.2125 -0.20725 -0.202 -0.19675 -0.1915 -0.18625 -0.181 -0.17575 -0.1705 -0.16525 -0.16 -0.15475 -0.1495 -0.14425 -0.139 -0.13375 -0.1285 -0.12325 -0.118 -0.11275 -0.1075 -0.10225 -0.097 -0.09175 -0.0865 -0.08125 -0.076 -0.07075 -0.0655 -0.06025 -0.055 -0.04975 -0.0445 -0.03925 -0.034 -0.02875 -0.0235 -0.01825 -0.013 -0.00775 -0.0025 0.00275 0.008 0.01325 0.0185 0.02375 0.029 0.03425 0.0395 0.04475 0.05 0.055 0.06 0.065 0.07 0.075 0.08 0.085 0.09 0.095 0.1

Axis name

AN "#phi [deg]"

Axis type

AT 1D BinEdges

Axis data

AD 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180

Axis name

AN "#theta [deg]"

Axis type

AT 1D BinEdges

Axis data

AD -180 -179 -178 -177 -176 -175 -174 -173 -172 -171 -170 -169 -168 -167 -166 -165 -164 -163 -162 -161 -160 -159 -158 -157 -156 -155 -154 -153 -152 -151 -150 -149 -148 -147 -146 -145 -144 -143 -142 -141 -140 -139 -138 -137 -136 -135 -134 -133 -132 -131 -130 -129 -128 -127 -126 -125 -124 -123 -122 -121 -120 -119 -118 -117 -116 -115 -114 -113 -112 -111 -110 -109 -108 -107 -106 -105 -104 -103 -102 -101 -100 -99 -98 -97 -96 -95 -94 -93 -92 -91 -90 -89 -88 -87 -86 -85 -84 -83 -82 -81 -80 -79 -78 -77 -76 -75 -74 -73 -72 -71 -70 -69 -68 -67 -66 -65 -64 -63 -62 -61 -60 -59 -58 -57 -56 -55 -54 -53 -52 -51 -50 -49 -48 -47 -46 -45 -44 -43 -42 -41 -40 -39 -38 -37 -36 -35 -34 -33 -32 -31 -30 -29 -28 -27 -26 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180

Axis name

AN "#zeta [deg]"

Axis type

AT 1D BinEdges

Axis data

AD 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100 104 108 112 116 120 124 128 132 136 140 144 148 152 156 160 164 168 172 176 180 184 188 192 196 200 204 208 212 216 220 224 228 232 236 240 244 248 252 256 260 264 268 272 276 280 284 288 292 296 300 304 308 312 316 320 324 328 332 336 340 344 348 352 356 360

Axis name

AN "#sigma [deg]" "#tau [deg]"

Axis type

AT 2D HEALPix

Axis data

AD -1 RING

Axis name

AN "Distance [cm]"

Axis type

AT 1D BinEdges

Axis data

AD 0.25 1000

Type ResponseMatrixONSparse

RD 86 1386 170 177 4 0 0 0 1

[jdbuhler]

OK, this doesn't seem too bad -- many of the axes (of course) have different names, so the field sanity checking code in the RspConverter needs to be extended accordingly. But I'm guessing there would be no real change to the conversion otherwise -- we still have the NuLambda and Ei dimensions, and the compression/chunking scheme is unlikely to need to change.