Trying to find the min non-zero value of a [925x902] matrix

I am trying to find the minimum non-zero value of a [925x902] matrix called D1.Z

i have tried:

min(D1.Z(D1.Z > 0));

D1.Z(D1.Z==0) = nan; then min(min(D1.Z));

Error comes up saying the 'index exceeds the number of array elements (1)'

Anyway around these?

Answer 1

[Star Strider]

Perhaps —

D1.Z = rand(925,902)                                % Create Test Matrix

D1 = struct with fields:
    Z: [925×902 double]

D1.Z(randi(numel(D1.Z),1,5)) = 0;                   % Set Some Elements To Zero
Check = min(D1.Z,[],'all')                          % Check Matrix To Demonstrate Replacement Effective

Check = 0

MinZ = min(D1.Z(D1.Z~=0),[],'all')                  % Return Minimum ~= 0

MinZ = 1.2686e-06

.

[Todd Pierce]

Thanks,

But i just tried this and still ot the same error message

this is what i entered as you mentioned:

MinZ = min(D1.Z(D1.Z~=0),[],'all')

this is the error message i still get

Index in position 1 exceeds array bounds (must not exceed 1).

[Star Strider]

My pleasuure.

I am not absolutely certain what the problem is, however it could be that you have a scalar variable named ‘min’ that is overshadowing the min function, and MATLAB is attempting to address into it.

Running this from the Command Window or a script:

which min '-all'

built-in (/MATLAB/toolbox/matlab/datafun/min)
built-in (/MATLAB/toolbox/matlab/datafun/@double/min)            % Shadowed double method
built-in (/MATLAB/toolbox/matlab/datafun/@int16/min)             % Shadowed int16 method
built-in (/MATLAB/toolbox/matlab/datafun/@int32/min)             % Shadowed int32 method
built-in (/MATLAB/toolbox/matlab/datafun/@int64/min)             % Shadowed int64 method
built-in (/MATLAB/toolbox/matlab/datafun/@int8/min)              % Shadowed int8 method
built-in (/MATLAB/toolbox/matlab/datafun/@logical/min)           % Shadowed logical method
built-in (/MATLAB/toolbox/matlab/datafun/@single/min)            % Shadowed single method
built-in (/MATLAB/toolbox/matlab/datafun/@uint16/min)            % Shadowed uint16 method
built-in (/MATLAB/toolbox/matlab/datafun/@uint32/min)            % Shadowed uint32 method
built-in (/MATLAB/toolbox/matlab/datafun/@uint64/min)            % Shadowed uint64 method
built-in (/MATLAB/toolbox/matlab/datafun/@uint8/min)             % Shadowed uint8 method
/MATLAB/toolbox/matlab/datatypes/categorical/@categorical/min.m  % Shadowed categorical method
/MATLAB/toolbox/matlab/datatypes/datetime/@datetime/min.m        % Shadowed datetime method
/MATLAB/toolbox/matlab/datatypes/duration/@duration/min.m        % Shadowed duration method
/MATLAB/toolbox/matlab/timeseries/@timeseries/min.m              % Shadowed timeseries method
min is a built-in method                                         % Shadowed connector.internal.LoggerLevel method
min is a built-in method                                         % Shadowed matlab.internal.lang.capability.Capability method
min is a built-in method                                         % Shadowed matlab.lang.OnOffSwitchState method
min is a built-in method                                         % Shadowed matlab.internal.reference.property.RefEntityType method
min is a built-in method                                         % Shadowed matlab.internal.reference.api.EntityPrecision method
min is a built-in method                                         % Shadowed matlab.internal.reference.property.DeprecationStatus method
min is a built-in method                                         % Shadowed matlab.internal.reference.property.FunctionType method
min is a built-in method                                         % Shadowed matlab.internal.reference.api.EntityCaseSensitivity method
min is a built-in method                                         % Shadowed mf.zero.meta.Language method
min is a built-in method                                         % Shadowed dig.config.CommandType method
min is a built-in method                                         % Shadowed dig.config.HorizontalAlignment method
min is a built-in method                                         % Shadowed dig.model.DisplayState method
min is a built-in method                                         % Shadowed dig.model.EventDataType method
min is a built-in method                                         % Shadowed dig.model.FunctionType method
min is a built-in method                                         % Shadowed dig.model.ValidInBdType method
min is a built-in method                                         % Shadowed dig.model.ViewMode method
min is a built-in method                                         % Shadowed simulink.FindSystemTask.Status method
min is a built-in method                                         % Shadowed sl.data.adapter.AdapterDiagnostic method
min is a built-in method                                         % Shadowed sl.data.adapter.AdapterType method
min is a built-in method                                         % Shadowed sl.data.adapter.ChangeType method
min is a built-in method                                         % Shadowed slid.SourceIssue method
min is a built-in method                                         % Shadowed slid.broker.SourceManagerSourceKind method
min is a built-in method                                         % Shadowed dastudio_util.cooperative.AsyncFunctionRepeaterTask.Status method
min is a built-in method                                         % Shadowed coderdictionary.data.AccessFunctionSignaturesEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.AccessInterfaceEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.AccessModeEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.AllowedAccessEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.DataAccessEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.DataAccessTypeEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.DataInitEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.DataInstantiationEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.LatchingModeEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.PlacementEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.ScopeEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.StatementsSurroundEnum method
min is a built-in method                                         % Shadowed coderdictionary.data.StatusEnum method
min is a built-in method                                         % Shadowed matlab.unittest.Verbosity method
min is a built-in method                                         % Shadowed matlab.unittest.internal.fixtures.FolderScope method
min is a Java method                                             % Shadowed java.lang.Double method
min is a built-in method                                         % Shadowed matlab.internal.timer.CallBackTypeEnum method
min is a built-in method                                         % Shadowed matlab.internal.timer.BusyModeEnum method
min is a built-in method                                         % Shadowed matlab.internal.timer.ExecutionModeEnum method
min is a built-in method                                         % Shadowed matlab.pyclient.Status method
/MATLAB/toolbox/matlab/bigdata/@tall/min.m                       % Shadowed tall method
/MATLAB/toolbox/coder/half/@half/min.p                           % Shadowed half method
/MATLAB/toolbox/finance/ftseries/@fints/min.m                    % Shadowed fints method
/MATLAB/toolbox/nnet/deep/@dlarray/min.m                         % Shadowed dlarray method
/MATLAB/toolbox/parallel/gpu/@gpuArray/min.m                     % Shadowed gpuArray method
/MATLAB/toolbox/parallel/parallel/@codistributed/min.m           % Shadowed codistributed method
/MATLAB/toolbox/symbolic/symbolic/@sym/min.m                     % Shadowed sym method

should produce something similar to this list. If the first entry is:

min is a variable.

you have found the problem.

The solution is to rename it to something else that is meaningful in the context of the code and does not overshadow any MATLAB functions.

.

[Todd Pierce]

Ahh yes, thank you i had quite a large list of variables and did not notice the variable 'min' having got rid of it the value can now be returned.

Seperately how would i turn all of the zero values into NaN values so that i can create a boxplot of all the non-zero values in the grid?

[Star Strider]

My pleasure!

D1.Z = rand(10);                                    % Create Test Matrix
D1.Z(randi(numel(D1.Z),1,5)) = 0;                   % Set Some Elements To Zero
disp(D1.Z)

    0.0981    0.3040    0.6708    0.4800    0.2448    0.1338    0.1590    0.3726    0.3224    0.5954
    0.2704    0.1612    0.6804    0.3858    0.0341    0.6925    0.5445    0.2561    0.0907    0.3257
    0.6093    0.7979    0.8442    0.7056    0.8739    0.8291    0.3115    0.1651    0.4542    0.5793
    0.0105    0.6334    0.3431         0    0.4378    0.3250    0.4830    0.9645    0.0730    0.8571
    0.6668    0.6214    0.8889    0.4468    0.6260    0.1934    0.5117    0.1757    0.4642    0.3526
    0.4422    0.4248    0.5606    0.5738    0.7770    0.8318    0.2828    0.9010    0.5335    0.6002
    0.0925         0    0.0005    0.1884         0    0.2864    0.3049    0.2858         0    0.7415
    0.7620    0.0161    0.3153    0.2085    0.4788    0.4179    0.1885    0.6728    0.6932    0.9720
    0.6522    0.3710    0.8991    0.3624    0.2177    0.5413    0.8296    0.0901    0.6225    0.5573
    0.7923    0.2059    0.4223    0.2446    0.7650    0.4297    0.4614         0    0.8909    0.6612

D1.Z(D1.Z == 0) = NaN;                              % Convert '0' To 'NaN'
disp(D1.Z)

    0.0981    0.3040    0.6708    0.4800    0.2448    0.1338    0.1590    0.3726    0.3224    0.5954
    0.2704    0.1612    0.6804    0.3858    0.0341    0.6925    0.5445    0.2561    0.0907    0.3257
    0.6093    0.7979    0.8442    0.7056    0.8739    0.8291    0.3115    0.1651    0.4542    0.5793
    0.0105    0.6334    0.3431       NaN    0.4378    0.3250    0.4830    0.9645    0.0730    0.8571
    0.6668    0.6214    0.8889    0.4468    0.6260    0.1934    0.5117    0.1757    0.4642    0.3526
    0.4422    0.4248    0.5606    0.5738    0.7770    0.8318    0.2828    0.9010    0.5335    0.6002
    0.0925       NaN    0.0005    0.1884       NaN    0.2864    0.3049    0.2858       NaN    0.7415
    0.7620    0.0161    0.3153    0.2085    0.4788    0.4179    0.1885    0.6728    0.6932    0.9720
    0.6522    0.3710    0.8991    0.3624    0.2177    0.5413    0.8296    0.0901    0.6225    0.5573
    0.7923    0.2059    0.4223    0.2446    0.7650    0.4297    0.4614       NaN    0.8909    0.6612

That should produce the desirred result.

.

[Todd Pierce]

Thank you

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.