Where can I find some help with CACE histogram plot? I found some info in the source code, but I am failing to make it work. My testbench generates a vector with voltages from various monte carlo runs, like this:

.control
let it = 0
let iterations = \{iterations|maximum\}
let output_option = \{output_option\}
let vref_data = vector(iterations)
let vref_mean = 0
print iterations
print vref_data
dowhile it < iterations
	reset
	op
	let vref_data[it] = V(vref)
	let vref_mean = vref_mean + V(vref)
	let it = it + 1
end
if output_option = 0
	print vref_data
	wrdata \\\{simpath\\\}/\\\{filename\\\}_\\\{N\\\}.data vref_data
	quit
end
let vref_mean = vref_mean / iterations
if output_option = 1
	print vref_mean
	wrdata \\\{simpath\\\}/\\\{filename\\\}_\\\{N\\\}.data vref_mean
	quit
end
let vref_deviation = 0
let it = 0;
dowhile it < iterations
	let vref_deviation = vref_deviation + (vref_data[it]-vref_mean)^2
	let it = it+1
end
let vref_deviation = (vref_deviation / iterations)^0.5
let vref_accuracy = 3 * vref_deviation / vref_mean
print vref_accuracy
wrdata \\\{simpath\\\}/\\\{filename\\\}_\\\{N\\\}.data vref_accuracy
quit
.endc

Here is what I am using inside the project file:

+
	name:			vref_histogram
	status:			skip
	description:	Reference Voltage vs Process Variation
	display:		Vref vs Process Variation
	unit: 			V
	simulate {
		tool:		ngspice
		template:	tb_vref_mc.spice
		format:		ascii .data null result
	}
	plot {
		type: 'histogram'
		filename: vref_vs_process.png
		xaxis: result
	}
	conditions {
		name: iterations
		maximum: 10

		+
		name: output_option
		typical: 0
	}

@Adan Kvitschal: What does your output data file look like? Do you see the variation in results in the file?

Thanks for the quick reply, I am trying to locate the file now

In the simulation directory (usually

ngspice/

), but you will need to select "Keep files after simulation" from "Settings".

i got just one line in the file

1.00000000e+00  1.22060486e+00

Ah. Okay, first you need to do

set appendwrite

.

I am not an expert using ngspice to process data, so I might be comiting a simple mistake

I think that works best if you set

appendwrite

after the first write, so the first write creates the data file and after that they all append to it.

I tought there would have ocurred a single write using this:

wrdata \\\{simpath\\\}/\\\{filename\\\}_\\\{N\\\}.data vref_data

Oh, right. But it's a vector. . . maybe you need

$&vref_data

and not just

vref_data

?

the backslashes appear when I open the file in vscode, they dont seem to be causing any problems

Try

set wr_singlescale

. Then you should get only one reference value followed by your vector of 10. However, I'm not sure how that works in CACE with the "format" line. I'm sure I have handled vectors on the result line but I'd have to go back and see how I was handling it.

That puts only one ocurrence of avdd in the data

1.80000000e+00  1.22372000e+00  1.22527000e+00  1.22636000e+00  1.22325000e+00  1.22343000e+00  1.22383000e+00  1.22062000e+00  1.22614000e+00  1.22326000e+00  1.22702000e+00

I think the data should be in columns, so the vector indices may be the way to fix this. My temp sweep for instance works because it is formated like this:

-4.00000000e+01  1.25328232e+00 
-3.50000000e+01  1.25289129e+00 
-3.00000000e+01  1.25259234e+00 
-2.50000000e+01  1.25237311e+00 
-2.00000000e+01  1.25222288e+00 
-1.50000000e+01  1.25213246e+00 
-1.00000000e+01  1.25209394e+00 
-5.00000000e+00  1.25210055e+00 
 0.00000000e+00  1.25214646e+00 
 5.00000000e+00  1.25222661e+00 
 1.00000000e+01  1.25233665e+00 
 1.50000000e+01  1.25247275e+00 
 2.00000000e+01  1.25263159e+00 
 2.50000000e+01  1.25281023e+00 
 3.00000000e+01  1.25300611e+00 
 3.50000000e+01  1.25321695e+00 
 4.00000000e+01  1.25344076e+00 
 4.50000000e+01  1.25367581e+00 
 5.00000000e+01  1.25392061e+00 
 5.50000000e+01  1.25417391e+00 
 6.00000000e+01  1.25443475e+00 
 6.50000000e+01  1.25470249e+00 
 7.00000000e+01  1.25497685e+00 
 7.50000000e+01  1.25525806e+00 
 8.00000000e+01  1.25554702e+00 
 8.50000000e+01  1.25584550e+00

This will work:

set wr_singlescale
let it = 1
wrdata ngspice/test.data vref_data[0]
set appendwrite
dowhile it < iterations
        wrdata ngspice/test.data vref_data[it]
        let it = it + 1
end

works! thank you

Except for the fact that the Y axis got labeled with "result" instead of "count". Looks like a minor bug I'll have to track down.