Arthur Evans Comments - Answer Overflow

Arthur Evans

•Created by Martin Dudek on 5/10/2024 in #questions

What UnsafePointer can point to and allocate mem for?

(Ultimately collections should only require Movable not Copyable, but right now they require both, and set isn't currently Copyable.)

15 replies

MModular

•Created by Martin Dudek on 5/10/2024 in #questions

What UnsafePointer can point to and allocate mem for?

That seems like a bug. You should totally be able to have a list of Sets or a dict of Sets or dare I say it a Set of Sets ... please open an issue!

15 replies

MModular

•Created by Martin Dudek on 5/10/2024 in #questions

What UnsafePointer can point to and allocate mem for?

Oh, I see... Set doesn't have CollectionElement. Weird.

15 replies

MModular

•Created by Martin Dudek on 5/10/2024 in #questions

What UnsafePointer can point to and allocate mem for?

Any @value struct should qualify as a CollectionElement I believe.

15 replies

MModular

•Created by vmois on 12/30/2023 in #questions

Owned convention does not destroy variable after transferring ownership

A quick answer on the current state of affairs which might shed a little light here: the current Pointer is unsafe. The owned convention should force a copy of the value, but copying a Pointer doesn't copy the memory that it points to. I'm not positive, but I suspect you're seeing the same thing in the Pointer case and the Int case--the ^ operator is basically ignored because an Integer is just a value in a register, and we don't need to destruct it. (And a pointer is basically just an integer.) In the case of the integer, you can see that the value was copied--the x in main and the x in take_value() end up with different values. The string example does what you'd expect it do with any non-trivial type: the value is destructed after you pass it in to take_text(). You'd see the same result if you used a DynamicVector in your first example instead of a raw Pointer.

5 replies

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•Created by Henk-Jan Lebbink on 12/20/2023 in #questions

Does a pragma exist to switch off `mojo format`

Because it took me a while to find in the black docs (yes, "basics" was the last place I looked ...): https://black.readthedocs.io/en/stable/usage_and_configuration/the_basics.html#ignoring-sections

5 replies

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•Created by VikasPoddar001 on 12/19/2023 in #questions

change in syntax for types declaration

Also, the types themselves are different. I.e., Int versus int isn't a matter of the compiler looking at capitalization... int is a Python class. Int is a Mojo struct.

4 replies

MModular

•Created by Vijay Yadav on 12/19/2023 in #questions

How to convert string to float value?

Here is the really cheesy way to do it:

let fstr = "1.345E-3"
let float = Python.evaluate("float(" + fstr + ")").to_float64()

let fstr = "1.345E-3"
let float = Python.evaluate("float(" + fstr + ")").to_float64()

12 replies

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•Created by clarkezone on 12/15/2023 in #questions

Difference between Float32 and DType.float32

They're both defined in the standard library. There's currently no mechanism to add new DTypes (there is already one for bfloat16, but I don't know how complete the support is). You can find the list of current DTypes here: https://docs.modular.com/mojo/stdlib/builtin/dtype.html#dtype Theoretically you can write a new type, as described in Low-Level IR with Mojo: https://docs.modular.com/mojo/notebooks/BoolMLIR.html ... but this is a really advanced topic that we don't have any documentation for at the moment.

7 replies

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•Created by Noe on 12/9/2023 in #questions

Term paper about Mojo - Open questions

Excellent. Good luck with the term paper!

8 replies

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•Created by clarkezone on 12/15/2023 in #questions

Difference between Float32 and DType.float32

I'm going to take a short tangent here. I swear it's related. I don't know if you've touched on SIMD yet--it's another type that tends to confuse folks, and this part is kind of related to AI/ML. SIMD (single instruction, multiple data) is a technique for parallelizing data operations when you want to do a lot of similar operations. A Mojo SIMD type is a small, fixed-sized vector--or array--of numeric data types. These are used heavily in low-level AI/ML programming, so they're built right in to the Mojo standard library. A SIMD[DType.float32, 8] is a vector of 8 Float32 values. You can do something fancy like take the square root of all of the values with a single operation:

var s = SIMD[DType.float32, 8](1, 2, 3, 4, 5, 6, 7, 8)
var s2 = math.sqrt(s)

var s = SIMD[DType.float32, 8](1, 2, 3, 4, 5, 6, 7, 8)
var s2 = math.sqrt(s)

With SIMD, doing 8 operations at once takes about the same time as doing one—so you can see why this is desirable when you're crunching a lot of numbers. OK, so I told you this was related, and it is. What exactly is that Float32 type. you're using? It's actually an alias for SIMD[DType.float32, 1]. That's right, it's a SIMD vector holding one 32-bit floating point number. When you create a DTypePointer[DType.float32], it's basically the same as creating pointer to an array of Float32 scalar values.

7 replies

MModular

•Created by clarkezone on 12/15/2023 in #questions

Difference between Float32 and DType.float32

TL;DR: DType describes a data format in the abstract. Types like DTypePointer, SIMD, and Buffer use DTypes to describe the data they store. Float32 is a concrete type which you can instantiate. These aren't really related to AI/ML or Python.Float32 is a type. You can instantiate a Float32, like you did in your code (Float32(i)). DType is a structure that provides various utilities for working with data types, including enumerated values (enums) describing various data types, like float32. So DType.float32 is a value that describes a type. It's used in a variety of generic types like DTypePointer and SIMD to describe the type of data being stored. You can't create a DType.float32, but you can create a Float32(which is a scalar value of that dtype) or a Buffer or SIMD vector made up of DType.float32 values.

7 replies

MModular

•Created by stu002 on 12/15/2023 in #questions

can I implement a trait for a third party type?

You're correct. You cannot currently implement a trait for a type that you don't control. The team fully intends to fix this, but there are a couple of possible approaches (for example, allowing implicit conformance to traits, or an extension mechanism like Swift (in Rust, adding an implementation I think). Stay tuned.

3 replies

MModular

•Created by Noe on 12/9/2023 in #questions

Term paper about Mojo - Open questions

@Noe your compiled binary is loading the CPython interpreter (from a shared library). Objects constructed by your code are Mojo objects--including literals. If you look at the doc for PythonObject: https://docs.modular.com/mojo/stdlib/python/object.html#pythonobject You'll see that every PythonObject has a py_object field, which is a pointer to a PyObject--that's the representation of a native Python object in Python's C API. When you import a Python module, you get a PythonObject wrapping that module. When you call a function on that object, PythonObject in turn makes a call to the CPython interpreter, passing it the underlying PyObject pointer and Python versons of any (Mojo) arguments you pass in. Whatever Python object that function returns gets wrapped as another PythonObject, and so on. For more information on PyObject and the Python interpreter interface, you might start here: https://docs.python.org/3/c-api/intro.html

8 replies

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•Created by roopesh puthalath on 9/20/2023 in #questions

Bug, while loop Re-setting values?

Great, glad to hear it!

17 replies

MModular

•Created by roopesh puthalath on 9/20/2023 in #questions

Bug, while loop Re-setting values?

def open_file_explorer() -> String:

17 replies

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