Adding linear regression model breaks flow

[jackpanderson]

Describe the bug As said in the title, adding the linear regression model in the .py config settings breaks the characterization.

Version 1.2.15

To Reproduce Adding model_name = "linear_regression" to the model config

Logs LIB: Characterizing... [openram.characterizer.lib/prepare_tables]: Slews: [0.00125 0.005 0.04 ] [openram.characterizer.lib/prepare_tables]: Loads: [ 1.7225 6.89 27.56 ] [openram.characterizer.lib/prepare_tables]: self.load_slews : [(1.7225, 0.00125), (6.89, 0.00125), (27.56, 0.00125), (1.7225, 0.005), (6.89, 0.005), (27.56, 0.005), (1.7225, 0.04), (6.89, 0.04), (27.56, 0.04)] [openram.characterizer.lib/characterize_corners]: Characterizing corners: [('TT', 1.8, 25)] [openram.characterizer.lib/characterize_corners]: Corner: ('TT', 1.8, 25) [openram.characterizer.lib/characterize_corners]: Writing to /home/jande180/CARP/OpenRAM/macros/sram_32_32_sky130_1r1rw/sram_32_32_sky130_1r1rw_TT_1p8V_25C.lib [openram.characterizer.regression_model/get_lib_values]: Characterizing SRAM using regression models. Traceback (most recent call last): File "/home/jande180/CARP/OpenRAM/sram_compiler.py", line 74, in s.save() File "/home/jande180/CARP/OpenRAM/compiler/sram.py", line 163, in save lib(out_dir=OPTS.output_path, sram=self.s, sp_file=sp_file) File "/home/jande180/CARP/OpenRAM/compiler/characterizer/lib.py", line 46, in init self.characterize_corners() File "/home/jande180/CARP/OpenRAM/compiler/characterizer/lib.py", line 163, in characterize_corners self.characterize() File "/home/jande180/CARP/OpenRAM/compiler/characterizer/lib.py", line 175, in characterize self.compute_delay() File "/home/jande180/CARP/OpenRAM/compiler/characterizer/lib.py", line 646, in compute_delay char_results = m.get_lib_values(self.load_slews) File "/home/jande180/CARP/OpenRAM/compiler/characterizer/regression_model.py", line 72, in get_lib_values models = self.train_models() File "/home/jande180/CARP/OpenRAM/compiler/characterizer/regression_model.py", line 138, in train_models self.output_names = get_data_names(data_path)[self.num_inputs:] File "/home/jande180/CARP/OpenRAM/compiler/characterizer/analytical_util.py", line 22, in get_data_names with open(file_name, newline='') as csvfile: FileNotFoundError: [Errno 2] No such file or directory: '/home/jande180/CARP/OpenRAM/technology/sky130/sim_data/sim_data.csv' make: *** [Makefile:82: sram_32_32_sky130_1r1rw.ok] Error 1

[mguthaus]

This mode requires you to precharacterize a bunch of memories in that file so that it can use regression to predict models for new memories. We haven't done that for Skywater yet and instead recommend regular characterization. This is from the following MS thesis: https://www.proquest.com/openview/273a1089a88606160de418f5b75f29e7/1.pdf?pq-origsite=gscholar&cbl=18750&diss=y

The error should definitely be improved though.