# Ashfaq Ahmed

I am a first-year Ph.D. student at Brown University. My research interest lies in sea-ice dynamics, and transport phenomena.

**Programming Languages:**

Python, MATLAB

**Spoken Languages:**

English, Hindi, Spanish, Bengali

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**Content Feed**

Question

How to perform t-test for a temperature anomaly data set?

Hi all, let's say, I have a 376x268x235 3D matrix, with values ranging from -2.5°C to 0.65°C. Here, 376x268 is the grid system...

27 dagar ago | 1 answer | 0

### 1

answerQuestion

How to plot the best fitted ellipse or circle?

Hi all, I have a data set (attached here) that has two arrays. I want to plot them in a polar graph and want to find out the b...

ungefär en månad ago | 4 answers | 0

### 4

answersQuestion

How to locate a specific point within a grid system?

Hi all, I have an interesting problem where I am stuck for the last couple of days. So, any feedback from you will be highly a...

3 månader ago | 1 answer | 0

### 1

answerQuestion

Locating any point from a meshgrid

Hi, I have a 161x161 double size Latitude matrix for a stereographic projection of north pole. If I contour plot it, it looks ...

3 månader ago | 1 answer | 0

### 1

answerQuestion

How to plot locations on a polar stereographic map?

Hi all! I have a list of Latitude coordinates, LAT = [85.6494200000000 85.6510100000000 85.6525200000000 85.6539900000000 85...

3 månader ago | 1 answer | 0

### 1

answerQuestion

How can I plot Arctic coastlines?

Hi! I have a sea level pressure gradient plot in a grid system which I want to show in the Arctic polar stereographic map. The l...

3 månader ago | 1 answer | 0

### 1

answerQuestion

'Polyfit' vs 'Detrend' function

Hi al, I have a quick question regarding how does the 'Detrend' function work. Is it a linear regression method? And If we want ...

4 månader ago | 1 answer | 0

### 1

answerQuestion

How to calculate the average of a cell array?

Hi, I have a cell array like this - T = {[10, 1, 30], [15, 2, 10], [20, 3, 20]} I want to calculate the mean of T in a way th...

4 månader ago | 2 answers | 0

### 2

answersQuestion

How can I plot this kind of graph with variable sample bins?

Hi all, can anyone please give me an idea on how can I plot this type of figure? The colorbar is tagged with the number of inten...

4 månader ago | 1 answer | 0

### 1

answerQuestion

Missing data retrieve from a periodic pattern.

Hi, I have a temperature record data set (attached) from 2005 to 2016. The temperature cycle is predictable because it's really ...

6 månader ago | 1 answer | 0

### 1

answerQuestion

How can I find out some specific dates from two date lists?

Hi, I have two date lists. DateList1.m contains dates from 1984 to 2022 (with many gaps) and DateList2.m constains dates from 20...

6 månader ago | 1 answer | 0

### 1

answerQuestion

How to calculate and plot this pcolor plot?

Hi, I have a 3D matrix of 1100x800x764 size. This forms a 1100 by 800 grid cell with 764 different samples. I want to calcul...

6 månader ago | 1 answer | 0

### 1

answerQuestion

How can I set the NaN values to black in a pcolor plot?

Hi all! Is there any way to set the NaN values as black/grey or any other color instead of white? I am using this code but it'...

7 månader ago | 2 answers | 0

### 2

answersQuestion

How to create a color plot based on the number of occurance?

Hi! I have a polar plot and we can see most of the data points fall within the 0° and 180° line. And the rest of the points are ...

7 månader ago | 1 answer | 0

### 1

answerQuestion

How to deseasonalize this temperature record?

Hi all! I have a temperature record (Temp.mat) that holds hourly temperature information from 2005 to 2019. Can anyone please g...

7 månader ago | 2 answers | 0

### 2

answersQuestion

How to filter out dates within a datetime list?

Hi! I have two timetable containing hourly information from 2005 to 2019. The first one NOAA.mat is a 131472x1 timetable and the...

7 månader ago | 1 answer | 0

### 1

answerQuestion

How to define color axis in a for loop?

Hi all, I wanted to define the color axis range based on the number of the ii in this for loop, but I don't know what is wrong, ...

7 månader ago | 1 answer | 0

### 1

answerQuestion

How to extract specific dates from a datetime table?

Hi! I have a datetime table (DATE1.mat) containing some dates from 1984 to 2022 at 10:00 am. I have another date timetable (DAT...

8 månader ago | 3 answers | 0

### 3

answersQuestion

How can I calculate the modulus and argument for every point in a plot?

Hi all, Suppose, I have a scattered plot like this - I want find out the θ, and r for every corresponding point. Can anyo...

8 månader ago | 1 answer | 0

### 1

answerQuestion

How to find the largest length of a cell array?

Hi, How can I find out the largest size of a cell array element? For example, this f array contains many doubles within it and...

8 månader ago | 1 answer | 0

### 1

answerQuestion

How to subcategorize dates from a datetime table?

Hi all, I have a datetime table in this Period.mat file (attached) where I have a date list starting from 01/01/2005 to 12/31...

8 månader ago | 1 answer | 0

### 1

answerQuestion

How can I list individual year from the datetime table?

Hi all, I have a datetime matrix (2003 to 2019, 17 years) and I want to list the range of index for individual years. For examp...

8 månader ago | 2 answers | 0

### 2

answersQuestion

How to perform a fast fourier transform (fft) or Lomb-Scargle (plomb) on this data set?

Hi all, I have this timetable with only two dataset: time series and temperature series. I want to calculate the frequency (p...

9 månader ago | 1 answer | 0

### 1

answerQuestion

How can I convert cell to a timetable?

Hi all, I have a table that is consists of both double (temperature, salinity) and cell array (sampling time). But I want to con...

9 månader ago | 1 answer | 0

### 1

answerQuestion

Signal Fitting with sine curve (and how to find out the phase shift?)

Hi! I have a temperature signal (Y-axis) consisting of 764 values that looks like this - And the time (X-axis) of this sig...

9 månader ago | 1 answer | 0

### 1

answerQuestion

How to write this in the title?

Hi, can any one please help me figuring out how can I write this title? For the value of A, t, and phi I want to use the no...

9 månader ago | 1 answer | 0

### 1

answerQuestion

Sinusoidal curve from discrete dataset

Hi! I have a few discrete data-set and when I plot them it looks like this - Can anyone please tell me how can I fit these ...

9 månader ago | 1 answer | 0

### 1

answerQuestion

How can I separate individual years from a timetable?

Hi! I have one table that contains 764 rows with different year's data point from 1984 to 2022. For example, row 1 to 8 are for...

9 månader ago | 1 answer | 0

### 1

answerQuestion

How can I run these codes in a for loop?

Hi! I understand that the variables should not be named dynamically. So, I would like to have an idea on how can I run these kin...

9 månader ago | 2 answers | 0

### 2

answersQuestion

Rebuilding a 3D matrix

Hi everyone! I am doing an operation where I will have to follow these algorithm steps. Can anyone please let me know how to pe...

9 månader ago | 1 answer | 0